1. Field of the Invention
This invention relates to a reinforcing tape or reinforcing sheet material to be attached to the end portion of a fastener tape which is intended for allowing attachment of a pin-and-socket separator.
2. Description of the Prior Art
The reinforcing tapes to be attached to the end portions of fastener tapes have been heretofore known in various types. The conventional reinforcing tapes include those which, for the sake of obviating the necessity of preparing reinforcing tapes dyed specially in various colors matched to the colors of dyed fastener tapes and consequently saving such time and labor as would otherwise be incurred in the inventory control, use transparent synthetic resin films in a superposed manner so as to show the colors of the dyed fastener tapes therethrough. For example, the reinforcing piece which is formed of two superposed transparent synthetic resin films having different melting points and is adapted to be applied fast to a fastener tape by melting that of the two films having a lower melting point as disclosed in Japanese Utility Model Publication No. (hereinafter referred to briefly as xe2x80x9cJUM-B-xe2x80x9d) 44-25,843 and the lateral application tape which is formed by superposing on one side of a transparent film of nylon 6 or nylon 66 a transparent polyester copolymer film having a melting point of not more than 200xc2x0 C. so as to show the color of the base fabric of the fastener tape therethrough as disclosed in published Japanese Patent Application, KOKAI (Early Publication) No. (hereinafter referred to briefly as xe2x80x9cJP-A-xe2x80x9d) 62-149,780 have been known to the art.
Since the reinforcing tapes formed of two layers of synthetic resin film as are disclosed in JUM-B-44-25,843 and JP-A-62-149,780 mentioned above are hard from the material point of view, they cannot be easily shaped by bending in conformity with the shape of the core portion of the fastener tape intended for permitting attachment of a pin-and-socket separator and, for this reason, the core portion of the fastener tape is not easily formed accurately in contour thereof. Further, these reinforcing tapes have the problem that when they are repeatedly bent, the bent lines thereof ultimately cause whitening possibly to the extent of jeopardizing the appearance of the reinforcing tapes.
To solve such problems, JP-A-8-299,033 and JP-A-10-306,262 filed by the assignee of this application propose reinforcing tapes using a transparent polyester elastomer film as a surface layer and having an adhesive layer superposed on the reverse side thereof.
The reinforcing tapes disclosed in JP-A-8-299,033 and JP-A-10-306,262 mentioned above have the surface layer (reinforcing layer) thereof formed of a polyester elastomer film and, therefore, enjoy the advantage of possessing flexibility enough to be folded in conformity with the contour of the core portion of the fastener tape as compared with the aforementioned reinforcing tape formed of synthetic resin film.
When the elastomer film is used for the reinforcing layer and this film happens to be supple, excellent in transparency and soft, however, since the film is deficient in resistance to washing and resistance to dry cleaning, the goods having fastener tapes attached thereto, on being washed or dry cleaned, encounter the problem that the reinforcing tape readily swells and the peel strength between the reinforcing tape and the fastener tape is degraded to the extent of rendering the reinforcing tape easy to peel.
It is, therefore, an object of the present invention to provide a reinforcing tape for a slide fastener, which exhibits high peel strength between the reinforcing tape and the fastener tape and possesses good resistance to washing and to dry cleaning in combination with high strength, while maintaining advantages of the elastomer film as the reinforcing layer of possessing suppleness and excellent transparency.
To accomplish the objects mentioned above, the present invention provides a reinforcing tape for a slide fastener, which tape comprises a transparent elastomer film and an adhesive layer superposed on the reverse side thereof and is characterized by further comprising an intermediate layer (anchor coat layer) interposed between the elastomer film and the adhesive layer and having a thickness thinner than the thickness of the elastomer film and that of the adhesive layer.
In a preferred embodiment of the present invention, a polyamide elastomer film or polyester elastomer film is used as the transparent elastomer film, a polyester-based anchor coat agent is used for the intermediate layer, and a polyester-based hot-melt adhesive is used for the adhesive layer. And the proper thickness of the elastomer film is 50 to 200 xcexcm, preferably 80 to 120 xcexcm, the proper thickness of the intermediate layer is 0.5 to 10 xcexcm, preferably 2 to 3 xcexcm, and the proper thickness of the adhesive layer is 30 to 120 xcexcm, preferably 50 to 60 xcexcm.
Since the reinforcing tape of the present invention has such structure that a relatively very thin intermediate layer is interposed between the elastomer film and the adhesive layer to improve the interlaminar strength thereof as mentioned above, it exhibits high peel strength between the reinforcing tape and the fastener tape and excels in resistance to washing and to dry cleaning, while maintaining advantages of the elastomer film as the reinforcing layer of possessing suppleness and excellent transparency. By bonding the reinforcing tape of the construction described above to the end portion of a fastener tape through the medium of the adhesive layer, particularly a polyester hot-melt adhesive layer, the fastener tape is enabled to acquire a reinforced part having the reinforcing tape joined thereto with thorough adhesive strength. Further, since the reinforcing tape of the present invention is transparent or translucent and excels in flexibility, it can be easily shaped in perfect conformity with the contour of the core portion of the fastener tape. When it is repeatedly folded, the folded portion is not whitened. Furthermore, when it is fixed to the fastener tape, it allows the color of the fastener tape to be directly seen therethrough and will not impair the appearance of the fastener tape.